Drainage chamber



FIG. 1 is a front top right perspective view of a drainage chamber showing the new design;

FIG. 2 is a front bottom right perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a rear elevation view thereof;

FIG. 7 is a right side view thereof, the left view being a mirror image thereof; and,

FIG. 8 is an enlarged, detailed view of a portion of the top plan view, as shown in FIG. 3.

The shape of the edge of the drainage chamber illustrated in FIG. 8 is mirrored on the opposite side. The broken lines of even length shown in the drawings depict portions of the drainage chamber that form no part of the claimed design. The broken lines of uneven length shown in the drawings show the boundary of the claimed design. 

CLAIM The ornamental design for a drainage chamber, as shown and described. 